The order of a Sunday worship service in a Presbyterian church includes prayer, music, Bible readings and a sermon based upon the scripture. The Sacraments, a time of personal response/offering and a sharing of community concerns are also parts of worship. Prayer is at the heart of worship. In prayer, through the Holy Spirit, people seek after and are found by the one true God who has been revealed in Jesus Christ. Prayer may be spoken, sung, offered in silence, or enacted. Music is a response which engages the whole self in prayer. To lead the congregation in the singing of prayer is a primary role of the choir and other musicians. They also pray on behalf of the congregation with introits, responses, and other musical forms. The church confesses the Scriptures to be the Word of God written, witnessing to God's self-revelation. Where that Word is read and proclaimed, Jesus Christ the Living Word is present by the inward witness of the Holy Spirit. For this reason the reading, hearing, preaching, and confessing of the Word are central to Christian worship. Use of the Common Lectionary at Olivet ensures a broad range of scripture readings as well as consistency and connection with the universal Church. The Sacraments of Baptism and the Lord's Supper are God's acts of sealing the promises of faith within the community of faith as the congregation worships. The Christian life is an offering of one's self to God. In worship the people are presented with the costly self-offering of Jesus Christ, are claimed and set free by him, and are led to respond by offering to him their lives, their particular gifts and abilities, and their material goods. Worship always offers opportunities to respond to Christ's call to become disciples by professing faith, by uniting with the church, and by taking up the mission of the people of God, as well as opportunities for disciples to renew the commitment of their lives to Jesus Christ and his mission in the world.